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Master of Science / Food Science / Kelly J.K. Getty / James L. Marsden / Escherichia coli O157:H7 outbreaks have been linked to leafy green produce and bagged spinach. The objective of this study was to evaluate a Photohydroionization (PHI) panel (novel advanced oxidation technology) and varying concentrations of lactic acid washes for controlling E. coli O157:H7 on baby spinach. Leaves were dip inoculated with a five-strain cocktail of E. coli O157:H7 inoculum having a concentration between 5-6 log CFU/ml. Leaves were submerged in inoculum for 30 s and dried for 1 h. Non-inoculated and inoculated leaves were washed for 30 s in food grade lactic acid diluted to concentrations of 0.5, 1.0, or 2.0% and allowed to dry for 10 min. For PHI treatment, leaves were placed under the PHI panel and treated for 1, 2, or 5 min on both sides for total treatment times of 2, 4 or 10 min. Following treatments, leaves were either sealed in low-density polyethylene bags or enumerated. Samples were enumerated at 0, 3, 7, 10, and 14 days following inoculation. Ten gram samples were diluted with sterile peptone and stomached for one min, and then 0.1 ml was plated onto sorbitol MacConkey agar with cefixime and tellurite plates that were incubated at 37°C for 24 h. For lactic acid treatments, E. coli O157:H7 populations were different (P < 0.05) compared to the control. There was no difference (P > 0.05) due to sampling time so sampling times where pooled together for each lactic acid concentration of 0.5, 1.0, and 2.0% and resulted in 2.01, 2.78, and 3.67 log CFU/g reductions, respectively. Leaves treated with 1.0% and 2.0% lactic acid had color degradation and were organoleptically unacceptable by day 14. When leaves were treated with PHI for 1, 2, or 5 min per side, E. coli O157:H7 populations were reduced 1.6, 1.49, or 1.95 log CFU/g, respectively. Leaves treated with PHI were not different from one another, but were different (P < 0.05) from the positive control. No color change occurred in leaves treated with PHI. The PHI panel and lactic acid washes of 0.5% or higher are effective in reducing E. coli O157:H7 in baby spinach.

<p>The principles of dye-sensitized solar cells were studied and are outlined in this thesis. An overview of the basic steps needed to create a DSC isfollowed by detailed experimental information on how to assemble the solar cells that were fabricated in this project. They were based on synthesizednanocrystalline ZnO thin films sensitized by chlorophyll a as well as isolated photopigments from spinach leaves. The nanocrystals werestudied using XRD, and it was confirmed that three different methods of synthesis resulted in ZnO crystals of a few nanometers. The solar cellswere assembled with Au electrodes in a sandwich configuration and their photovoltaic properties were measured. Overall light-to-electricity conversionwas low with the highest efficiency being 0.21 %. An astonishingly low efficiency of 0.0003 % was noted for a thin film which was not thermallytreated, and it is suggested that heat-treatment is of great importance. It was also found that photopigments from spinach can be extractedeasily and used as molecular sensitizer without any demanding purification steps.</p>

The principles of dye-sensitized solar cells were studied and are outlined in this thesis. An overview of the basic steps needed to create a DSC isfollowed by detailed experimental information on how to assemble the solar cells that were fabricated in this project. They were based on synthesizednanocrystalline ZnO thin films sensitized by chlorophyll a as well as isolated photopigments from spinach leaves. The nanocrystals werestudied using XRD, and it was confirmed that three different methods of synthesis resulted in ZnO crystals of a few nanometers. The solar cellswere assembled with Au electrodes in a sandwich configuration and their photovoltaic properties were measured. Overall light-to-electricity conversionwas low with the highest efficiency being 0.21 %. An astonishingly low efficiency of 0.0003 % was noted for a thin film which was not thermallytreated, and it is suggested that heat-treatment is of great importance. It was also found that photopigments from spinach can be extractedeasily and used as molecular sensitizer without any demanding purification steps.

Στην παρούσα μεταπτυχιακή εργασία παρουσιάζονται τα αποτελέσματα της διερεύνησης της επίδρασης της ιλύος βιολογικού καθαρισμού Καλαμάτας (Β.Κ.Κ.) στην ανάπτυξη του σπανακιού (Spinacia Oleracea) καθώς και στην απαορρόφηση N, P, K, Ca, Mg, ιχοστοιχείων Fe, Mn, Cu, Zn, βαρέων μετάλλων Pb, Ni, Cd και Cο από τα διάφορα μέρη του φυτού. Επιπλέον, η εργασία αυτή αποτελεί μια μελέτη της επίδρασης της συγκεκριμένης ιλύος και σε ορισμένους δείκτες ποιότητας των μιγμάτων ιλύος-εδάφους, όπως pH, αλατότητα, οργανική ουσία, ολικό ανθρακικό ασβέστιο, αλλά και σε ποσοτικούς δείκτες όπως η περιεκτικότητα σε ολικό άζωτο (Ν%), διαθέσιμο φωσφόρο (Ρ κατά Olsen), ανταλλάξιμα κατιόντα K, Ca, Mg, και συγκέντρωση ολικών, διαθέσιμων και ανταλλάξιμων ιχνοστοιχείων Fe, Mn, Cu, Zn, "βαρέων μετάλλων" Pb, Ni, Cd, Cr, Co. Τα αποτελέσματα προέρχονται μετά από πειραματική μελέτη που έγινε σε φυτά σπανακιού, αναπτυσσόμενα σε υποστρώματα που προέκυψαν από ανάμιξη εδάφους και ιλύος σε διάφορες αναλογίες, σε υπαίθριο προστατευμένο χώρο. Σκοπός της πειραματικής αυτής μελέτης είναι να ελεγχθούν και να αξιολογηθούν οι ιδιότητες που αποκτούν τα υπό εξέταση υποστρώματα από την προσθήκη ιλύος στο έδαφος ταυτόχρονα με την επίδραση στην ανάπτυξη του σπανακιού. Έτσι σε αδρές γραμμές μπορούμε να συμπεράνουμε ότι τα αποτελέσματα και η αξιολόγησή τους κατατείνουν στο ότι η ιλύς της μονάδας βιολογικού καθαρισμού της Καλαμάτας μπορεί να αξιοποιηθεί ως λίπασμα σε μικρές αναλογίες ιλύος/εδάφους και φαίνεται ότι η διάθεσή της στο έδαφος για γεωργικούς σκοπούς αποτελεί μια πολύ καλή μέθοδο διάθεσης, που πρέπει να εξετάζεται κατά προτεραιότητα. Ταυτόχρονα, επιβάλλεται η συνέχιση και επέκταση της σχετικής έρευνας, για αξιοποίηση και οικολογική διαχείριση της εν λόγω ιλύος. / This study investigates the effects of the sewage sludge of Kalamata Waste Water Treatment Plant (WWTP) both in the development of spinach (Spinacia oleracea) and the absorption of N, P, K, Ca, Mg, Fe, Mn, Cu, Zn, Pb, Ni, Cd and Co from various spinach plant parts. Parameters of soil - sludge mixtures are also considered during this study. Especially the effect of sludge on parameters such as pH, salinity, organic matter, total CaCO3, total nitrogen content (N%), available phosphorus, exchangeable K, Ca, Mg, and concentration of total, available and exchangeable Fe, Mn, Cu, Zn, Pb, Ni, Cd, Cr, Co. The experiments where conducted in Messinia and the results showed that sludge improves soil fertility. The application of sludge does not cause environmental problems in small proportions of sludge – soil mixture. In large quantities the addition of sludge is associated with potential toxicities and increased salinity in the soil as well as potential environmental problems from over-concentration of phosphorus but also heavy metals such as Pb, Ni and Cr. Special attention is need for Cd, not because of high concentration, but because of the special mobility it presents. Finally this study confirms the presence of a large number of interactions between nutrients, heavy metals and soil properties in soil and spinach. The evaluation of these interactions are of great importance because they help us to quantify elemental contribution of soil and plants, helps in understanding the problems of nutrition in preventing the occurrence of toxic problems at the expense of consumer health, the environment and ultimately to effective use of sludge. Finally, the sludge of Kalamata WWTP can be used as fertilizer in small proportions of sludge / soil mixtures and it seems that the disposal of sludge in soils for agricultural purposes is a very good method of disposal that must be considered.

Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2013-04-23T13:47:47Z No. of bitstreams: 1 Silvia Rocha.pdf: 838054 bytes, checksum: 4b1ce47b2cf6d9f32b6b110adf7bcfd4 (MD5) / Made available in DSpace on 2013-04-23T13:47:47Z (GMT). No. of bitstreams: 1 Silvia Rocha.pdf: 838054 bytes, checksum: 4b1ce47b2cf6d9f32b6b110adf7bcfd4 (MD5) Previous issue date: 2009 / O espinafre produzido e mais consumido no Brasil, denominado como espinafre da Nova Zelândia (Tetragonia expansa), difere significativamente do espinafre verdadeiro (Spinacia oleracea) produzido em muitos países do hemisfério norte. As diferenças ocorrem não apenas na classificação botânica, mas em muitas das características químicas dos vegetais. No presente trabalho, foram avaliados os teores de alguns nutrientes e antinutrientes contidos no espinafre comercializado na Bahia, sendo avaliados quatro diferentes procedimentos de digestão das amostras de espinafre com ácido nítrico em sistema aberto. Os resultados obtidos a partir dos diversos procedimentos de pré-tratamento da amostra foram comparados para os vários analitos investigados (Al, Ca, Fe, Cu, Zn, Mn, Mg) e indicaram vantagens da inserção de uma etapa de pré-digestão. Adicionalmente, foram realizados testes de extração dos metais sob investigação em água e em soluções com diferentes níveis de acidez na presença e ausência de agente quelante (ácido etilenodiaminotetracético – EDTA) para avaliação do nível de interação dos metais com o vegetal e, por conseguinte, a disponibilidade destes minerais. Os resultados levaram a acreditar que as interações de Mg(II), Cu(II) e Mn(II) com o espinafre seco eram fracas, enquanto que as interações com Al(III), Ca(II) e Fe(III) eram mais intensas, devido a condições mais drásticas (acidez da solução ou presença de quelante) foram necessárias para maximizar a extração destes metais. Ao considerar informações previamente reportadas sobre os elevados teores de oxalato em espinafre e seus efeitos antinutricionais, foram investigados os teores de oxalato em amostras secas oriundas de amostras de espinafre verdadeiro e espinafre da Nova Zelândia cultivado na Bahia, empregando permanganometria. Para tanto foram realizados estudos sobre as melhores condições para extração de oxalato variando a acidez da solução extratora e os resultados obtidos foram comparados com os apresentados na literatura. Finalmente, foram realizados testes para avaliação da possibilidade de enriquecimento de espinafre com íons metálicos a partir de sucessivas etapas de extração (dessorção) e concentração (sorção) do íon no vegetal. Pôde ser constatado que os maiores níveis de sorção (18 ± 3 mg g-1) e repetitividade foram obtidas para íons cálcio, possivelmente devido ao oxalato existente nos espinafres. / Salvador

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Thesis (M.Sc. Agriculture (Agricultural Economics)) -- University of Limpopo, 2022 / Spinach (Spinacia oleracea) is an important cash crop, which remains one of the largest sources of income and a way of sustaining livelihoods for rural households in South Africa. Smallholder farming in most rural areas of the Limpopo Province contributes to food security. However, the majority of smallholder farmers experience low agricultural productivity, low quantities and poor quality produce which reduce their chances of accessing markets. Hence, this study focused on identifying and analysing factors that determine productivity and market access by smallholder spinach farmers in the Polokwane Local Municipality, Limpopo Province. This area of research is important towards the development of smallholder farming where resources are limited, but high population growth is very common. The overall objective of the study was to examine farm and farmer characteristics that determine the productivity and market access of the smallholder vegetable farmers. In order to achieve the aim and objectives of this study, a multi-stage sampling technique was used to select 80 smallholder spinach farmers to collect primary data from them using structured questionnaires. Cobb-Douglas production function was used to examine factors that determine productivity level and the Two limit Tobit Model was also used to analyse factors that influence market access. The results from the Cobb-Douglas production function indicated that smallholder farmers in the study area are experiencing a decreasing return to scale, which suggests that they are over-utilising factors of production. Two-limit Tobit Model results on the socioeconomic factors that influence market access indicated that household size was statistically significant at 10%, distance to the market, extension contact and farming experience were statistically significant at 5% and educational level, quantity produced and market information was statistically significant at 1%. Based on the findings, several policy suggestions were made. These include strengthening of farmers‟ organisation, provision of market information, regular extension visits and provision of training to the farmers.

vegetable crops. Micro-Tom is a model tomato cultivar used for research due to its small size and short time to fruiting. This project evaluated I. walleriana and Micro-Tom transformed with Agrobacterium. The construct contained GFP (green fluorescent protein) and hygromycin antibiotic-resistant selectable markers, and the antisense sequence of open reading frame of INSV nucleocapsid protein (N). The N gene is expected to confer INSV resistance by RNA interference or gene silencing. The presence of transgenes was confirmed by PCR. Transgenic Impatiens was selfed for two generations. Transgenic Micro-Tom was selfed for 4 generations. Spinach was used as an INSV reservoir. Impatiens, spinach and Micro-Tom were mechanically inoculated with INSV and evaluated visually, with assay tests, ELISA testing, and PCR. Spinach was successfully infected with INSV six times of seven attempts. Impatiens and Micro-Tom had no successful inoculations of three and five attempts, respectively. / Master of Science